Normally-off operation power AlGaN/GaN HFET

We report on the novel normally-off GaN-based heterojunction field effect transistors (HFETs). The AlGaN/AlN/GaN heterostructure on Si (111) substrate was grown using a metalorganic chemical vapor deposition (MOCVD). The HFET for a normally-off operation was fabricated using the AlGaN/ C-GaN heterostructure. As a result, the HFET was operated at the condition of the positive gate bias. The breakdown voltage of FET was about 350 V. We also confirmed that the normally-off HFET was operated at 573 K. A normally-off operation using GaN based HFETs on the silicon substrate was thus confirmed for the first time.